Yep, is a screen in their consumer-site that shows all active billing plans. Two clicks to cancel. And that page is easier to find now (was buried before)
Yup. It's so obviously better for the consumer (and reduction of consumer support burden) that it's unbelievable that Stripe, or credit cards for that matter, don't have it.
For Stripe to offer that they would have to expose a "Stripe account" for buyers (the same thing the linked article complains about PayPal doing). For cards to do that they would have to move to only accepting merchant specific tokens you can revoke individually instead of the current state where the merchant (or their processor) has your card number.